Implantable medical devices designed to help repair damaged tissues have been successfully used for years. Some of these devices are used to patch damaged tissue and provide mechanical support to the tissues during healing. A simple form of these devices is a flexible patch-like sheet. The composition and morphology of the sheets are usually tailored to address a particular surgical need. In some cases, it is desirable to incorporate a reinforcing element into the flexible sheets. In addition to mechanical support, reinforcing elements often assist in handling and deployment of the implantable sheet devices. Ease of handling and deployment of flexible sheet devices are particularly desired when laproscopic instruments and procedures are used to implant the devices.
An example of one of these devices is disclosed by de la Torre in U.S. Pat. No. 5,368,602. de la Torre describes a patch made of a surgical mesh material having one or more semi-rigid frame-like support elements permanently secured to the mesh material along all or part of the border of the material. The semi-rigid support members are said to enable manipulation and positioning of the entire mesh area with conventional laproscopic instruments.
U.S. Pat. No. 5,695,525, issued to Mulhauser et al., discloses a semi-rigid framework in the form of a ring permanently attached to one side of a planar mesh material. The support ring is designed to prevent the planar mesh material from collapsing into crater-like defects in tissue by maintaining the mesh material in an expanded configuration across the defect site.
A repair patch similar to the Mulhauser et al. device is disclosed in U.S. Pat. No. 5,824,082, issued to Brown. The Brown patch utilizes a framework made of a metallic support wire. The support wire has shape-memory properties. The support wire is permanently attached to a preformed patch material along its periphery. The shape-memory characteristic of the support wire enables the repair patch to be rolled into a small cylindrical profile at room temperatures and alter its configuration to expand and flatten the patch material at body temperatures. The repair patch is said to reside between layers of tissue at a repair site and not require sutures or staples.
In U.S. Pat. No. 6,280,453, issued to Kugel et al., a hernia repair patch is disclosed having the form of a laminated mesh material with a framework made of a resilient monofilament spring permanently located between layers of the laminate. Once the patch is placed through an incision site in a hernia patient, the spring element assists in unfolding and expanding the patch into a planar configuration. The patch is provided with a pouch into which a surgeon can place a finger to position the patch across a hernia, rather than having to use a laproscopic instrument to position the patch.
A variation on the theme of implantable tissue repair devices having permanently attached reinforcing frameworks is disclosed by Gianturco in U.S. Pat. No. 5,258,000. The Gianturco device is initially implanted as an unsupported flexible bag having an internal space into which an elastic stiffener wire is subsequently threaded. The stiffener wire causes the bag to adopt a flattened shape. The flattened repair device with its stiffener wire is permanently secured to tissue surrounding the repair site with sutures or staples.
In surgical procedures that utilize a tissue repair material with a stiffener element, it may be desirable to remove the stiffener element from the repair material following at least partial attachment of the repair material to tissues of the repair site. In U.S. Pat. No. 5,370,650, issued to Tovey et al., an apparatus for positioning tissue repair meshes adjacent to body tissue is disclosed. The apparatus includes a delivery device with an arm that extends to place the tissue repair mesh into a surgical site. The arm has a stiffener element for the tissue repair mesh attached to its distal end. The tissue repair mesh is secured to the stiffener element with sutures sewn around the stiffener element and through holes in the mesh. The sutures can be sewn in such a way as to permit removal of the sutures from the tissue repair mesh following deployment. Prior to removal of the sutures from the mesh material, at least a portion the mesh material can be secured to tissues of the surgical site with sutures or staples. Once the tissue repair mesh is in place, the sutures holding the mesh to the stiffener element are removed. The delivery device is then separated from the tissue repair mesh and extracted from the surgical site.
A pneumatically operated deployment device for a tissue repair mesh is disclosed in U.S. Pat. No. 6,302,897, issued to Rousseau. The Rousseau device is an applicator with a tissue repair mesh simply placed on an external surface of an inflatable bladder. The bladder has two portions. The first portion is filled with air. The second portion is initially empty, but is fillable with the air from the first portion when external mechanical pressure is applied to the first portion. As the second portion is inflated, the applicator and tissue repair mesh are unfolded and the repair mesh pressed against a patient's tissue. Following deployment of the mesh, the bladder is removed from the surgical site by hand.
Farnsworth, et al. in U.S. Patent Publication No. 2004/0019360 disclose a tissue implant reinforced with a removable support member. The removable support member aids in placement and deployment of the tissue implant at an implantation site. The tissue implant and removable support member are both made of non-bioabsorbable materials.
In some applications, it would be useful to eliminate the need to remove a reinforcing member from a tissue repair device or material. In U.S. Pat. No. 6,599,323, Melican, et al. disclose a bioabsorbable tissue implant reinforced with a component that can be bioabsorbable for use in pelvic floor repair. The tissue implant comprises one or more layers of a bioabsorbable polymeric foam having pores with an open cell structure. The tissue implant is in the form of a porous foam material. The foam component is integrated with the reinforcing component such that the pores of the foam component penetrate the mesh of the reinforcing component and interlock with the reinforcing component. Melican et al., teach implants, such as patches, made from non-bioabsorbable material are undesirable, however.
None of these devices recognize the advantages of providing a non-bioabsorbable implantable sheet material with a resilient support member that is bioabsorbable. Such a device would have an adhesion scheme that permits the resilient support member to be initially held in place on the implantable sheet material with sufficient strength to withstand placement within and delivery from a laproscopic or similar surgical instrument. Yet the resilient support member would be removed from the implantable sheet material through a bioabsorption process and would not require further surgical procedures to remove the support member from the surgical site.
The bioabsorbable resilient support member would assist in changing the implantable sheet material from a compacted configuration to a more planar configuration. The support member could also provide an unobstructed border area in which a complete set of sutures or staples encompassing the non-bioabsorbable repair material could be put in place and tested. Such a device would optionally include features that assist in tactile and visual orientation of the device at a surgical site. The bio-absorbable support member could be combined with bioactive compounds that would be released at the implantation site independently or in combination with bioabsorption of the support member.